U.S. Pat. No. 6,375,170 discloses a spring arrangement having a double rolling-lobe flexible member. Such a spring arrangement can be assembled from two air spring components mounted as mirror images to each other. Each of the two spring elements includes essentially a rolling-lobe flexible member and a roll-off piston. A cover plate, which is required in a conventional air spring, can be omitted because a support device (support bell, outer jacket) is provided for laterally delimiting the rolling-lobe flexible member. In a preferred embodiment, the two rolling-lobe flexible members conjointly define a single piece, that is, the two rolling-lobe flexible members define a double rolling-lobe flexible member. The roll-off pistons are at the ends and the outer jacket is configured to be slightly conical at both ends.
In a deflection operation, the one part of the double rolling-lobe flexible member is compressed with the aid of the roll-off piston; while, at the same time, the other part of the double rolling-lobe flexible member is relieved of load with the aid of the other roll-off piston. Because of the conicality of the outer jacket and roll-off piston, there results a top/bottom asymmetry which has the consequence that the effective diameters of the two rolling lobes change wherefrom a soft spring action results.
In lieu of utilizing conicality of the roll-off pistons and/or the outer jacket, a top/bottom asymmetry can also be realized by differently wide roll-off pistons and/or an outer jacket which is of different width at the top and bottom thereof.
In contrast to a simple air spring, double rolling-lobe flexible member spring arrangements exhibit excellent guiding characteristics so that guide members are entirely or at least substantially unnecessary. However, because of the top/bottom asymmetry, considerable axial forces act between the roll-off piston pairs on the one hand and the outer jacket on the other hand. For this reason, it is absolutely necessary to fix the double rolling-lobe flexible member to the inner side of the outer jacket. The present day state of the art makes no suggestions as to how this necessary fixing should be realized.